THOEACIC DUCT AND HEART. 349 



h. The common iliac arteries, formed by the apparent 

 bifurcation of the aorta, run backwards and out- 

 wards to the hind-Umbs, along which they are 

 continued as the femoral arteries. In the abdo- 

 men each gives off the following branches. 



i. The ilio-lumbar artery runs outwards along 

 the posterior part of the dorsal wall of the 

 abdomen. 



ii. The internal iliac artery runs backwards along 

 the dorsal wall of the pelvic cavity. 



' iii. The vesical artery is a small branch which runs 

 backwards to the bladder. In the female it 

 also supplies the uterus. 



4. The pulmonary artery has already been described 

 (p. 340). 



Follow the branches of the pulmonary artery into the lungs. 



D. The Thoracic Duct. 



The thoracic duct is a slender thin-walled tube running 

 forwards through the thorax, and lying immediately to the 

 left of and dorsal to the aorta. Between the third and 

 fourth ribs it expands somewhat, and then turning inwards 

 traverses the thymus and opens into the left anterior vena 

 cava close to the left subclavian vein. 



The thoracic duct receives lymphatic vessels from almost 

 all parts of the body, and places these in communication with 

 the venous system. 



13. Dissection of the Heart. 



Gut across the great vessels, about half an inch from the 

 heart, carefully avoiding injury to the pneumogastric and 

 recurrent laryngeal nerves (see pp. 366 and 367). Bemove the 

 heart, and pin it down under ivater with the dorsal surface 

 upwards, passing the pins through the ventricles and the arch 

 of the aorta. Clean the roots of the several vessels, 



